AIRS CLEAR-SKY RETRIEVAL SOFTWARE Version 1.1 

(SSEC-CIMSS, University of Wisconsin, March 2006)                                     

==========================================================================
Changes from previous version:

1). New coefficient files created using the AIRS forward radiative transfer
    model SARTA from April 2005.
2). Modified execution script run_airs_rtv.scr which can now call an
     IDL (Interactive Data Language) routine to convert the output
     binary file into HDF4.
3). Modified matlab plot_bil_img.m routine to work with matlab 7.0
4). Includes directory containing 3 IDL routines which will convert
    input binary files into standard HDF4.
5). Small changes to the retrieval main Fortran 90 routine
    main_rtv_class_scang.f90 to ensure that the file is being
    written correctly on Sun platforms.

==========================================================================
 This directory contains tarfiles of the International MODIS and AIRS
 Processing Package (IMAPP) Products. This software is supported on the
 following platforms:
   
   (1) SUN, SunOS 5.9, sun4u sparc SUNW,Ultra-5_10, f90 compiler

   (2) LINUX, 2.4.18-27.xsmp, pgf90 compiler (Portland group)

 Note: This release consists of the AIRS clear sky retrieval software. 
       The following parameters are retrieved from this software:
     
       surface pressure [mbar]
       surface skin temperature [K]
       atmospheric temperature [K] at 101 pressure levels 
       total precipitable water [cm]
       atmospheric moisture [g/kg] at 101 pressure levels
       total ozone amount [dobson units]
       atmospheric ozone [ppmv] at 101 pressure levels
       surface emissivity at 15 wavenumbers
       surface reflectivity at 15 wavenumbers

 Latitude and longitude information are output in a separate binary output file.

 Note that the retrieval is performed on every pixel of the granule, except for
 those with radiances < -1.0 for at least one channel, however, retrievals
 performed in cloudy regions should only be considered valid above the
 cloud.  Users will have to know the cloud height, or filter out clouds
 and use clear-sky only retrievals to make use of the results.

**---------------------download directory-----------------------------**
     
   Clear_Sky_Retrievals.tar: AIRS retrieval source code with build and 
                       run instructions.  There is a run_airs_rtv.scr 
                       ksh script in the main directory that 
                       can be run on the test data sets provided
                       elsewhere on the ftp site.

   Documentation:
      AIRS_Clear_Sky_Retrievals.txt - Brief algorithm description
                                      and detailed output product
                                      description
      REFERENCES.txt: List of AIRS retrieval algorithm technical references.

   Coefficient Files: Found in the coefficients/sarta_apr05_big_endian and 
                      coefficients/sarta_apr05_little_endian directories
                      These files are required to run the software. 
                      Copy the files into the Clear_Sky_Retrievals/coeffs/
                      airs_L2_v106 directory that is created when you 
                      upack the clear sky retrievals tar file.
                      Choose either the big or little endian versions.
                      There are 198 total coefficent files.
      
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INPUTS: Found in the input_data directory
------------------------------------------
   Test input AIRS granule
      AIRS.2004.06.13.076.L1B.AIRS_Rad.v2.7.12.102.D04165080848.hdf

OUTPUTS: Found in the output_data directory
-------------------------------------------
   Test output files:
      Test file results for comparison to output data files

      Test output AIRS Retrieval binary image and header files:
        AIRS.2004.06.13.076.atm_prof_rtv_npc030.hdr
        AIRS.2004.06.13.076.atm_prof_rtv_npc030.img

      Test output AIRS Retrieval hdf file:
        AIRS.2004.06.13.076.atm_prof_rtv_npc030.hdf

      Test ouput from initial hdp extraction of parameters
        lat_g076_0613.dat (binary file latitude of the AIRS retrievals)
        lon_g076_0613.dat (binary file longitude of the AIRS retrievals)
        nodetype_g076_0613.txt (text file of words descending or ascending)
        freq_g076_0613.txt (text list of AIRS frequencies available)
        scang_g076_0613.dat (binary file containing scan angles for 
              each AIRS pixel)

VISUALIZATION SOFTWARE:  Found in the matlab directory
------------------------------------------------------
      Matlab source code to verify retrieval output:
          matlab/plot_bil_img.m
      Matlab format ancillary files:
          matlab/SARTA_plevs.mat   (contains the 101 AIRS pressure levels)
          matlab/srf_freq_2378.mat (contains the AIRS 2378 frequences 
                                     in wavenumbers)

      IDL source code to convert the binary retrieval file into an 
        HDF4 formatted file (these are unpacked with the clear sky
        retrieval tar file):  
          idl/create_uwl2_airs.pro  (main program)
          idl/hdf_sd_vardir.pro
          idl/hdf_sd_varread.pro


OUTPUT IMAGES:  Found in the images directory
---------------------------------------------
      Sample images produced by matlab software of output products
        emiss_900wvn.png
        humidity_700mbar.png
        ozone_10mbar.png
        rad_1000wvn.png
        refl_2518wvn.png
        spres.png
        temp_700mbar.png
        totozone.png
        tpw.png
        tskin.png